US20040021053A1 - Adjustable focusing composite for use in an optical profilometer system and method - Google Patents
Adjustable focusing composite for use in an optical profilometer system and method Download PDFInfo
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- US20040021053A1 US20040021053A1 US10/423,670 US42367003A US2004021053A1 US 20040021053 A1 US20040021053 A1 US 20040021053A1 US 42367003 A US42367003 A US 42367003A US 2004021053 A1 US2004021053 A1 US 2004021053A1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/30—Measuring arrangements characterised by the use of optical techniques for measuring roughness or irregularity of surfaces
- G01B11/303—Measuring arrangements characterised by the use of optical techniques for measuring roughness or irregularity of surfaces using photoelectric detection means
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/24—Measuring arrangements characterised by the use of optical techniques for measuring contours or curvatures
Definitions
- the invention relates to profilometers, and relates in particular to optical profilometers.
- Profilometers may be used for a variety of applications involving the determination of the depth or contours of a surface.
- Obtaining information regarding a profile of a surface is important in many areas of manufacturing and research.
- U.S. Pat. No. 5,565,987 discloses a profilometer system that includes a stylus for closely tracking a surface on a sub-nanometer scale
- U.S. Pat. No. 5,705,741 discloses a profilometer system that includes a constant force mechanism for biasing a stylus arm.
- Optical profilometers provide sensitive non-contact profilometry.
- Certain conventional optical profilometer systems such as those disclosed in Confocal Microscopy with a Refractive Microles - Pinhole Array , by M. Eisner, N. Lindlein, and J. Schwider, Optics Letters , v.23, no. 10 (May 1998); and Lithographic Patterning and Confocal Imaging with Zone Plates , D. Gil, R. Menon, D. Carter, and H. Smith, J. Vacuum Science and Technology B , 18(6) p. 2881-2885 (November/December. 2000) require that a lens array be physically moved to change the focal area during scanning.
- U.S. Pat. No. 4,579,454 discloses an optical profilometer in which the position of a focal point within a detector area is determined.
- U.S. Pat. No. 6,229,617 discloses an optical profilometer system in which light reflected from a surface is interfered with reference laser energy to produce an interference pattern.
- the invention provides an adjustable focusing composite for use in an optical profilometer system.
- the adjustable focusing composite includes a plurality of elements that are mutually spaced from another in a first position and provides a first focal area for an incident electromagnetic field having a first frequency incident at a first angle with respect to the plurality of elements.
- the adjustable focusing composite also includes an actuation unit for changing the focal area of the plurality of elements to provide a second,focal area for the incident electromagnetic field having the first frequency incident at the first angle with respect to the plurality of elements.
- FIGS. 1 and 2 show illustrative diagrammatic views of optical profilometer systems in accordance with various embodiments of the invention
- FIG. 3 shows an illustrative diagrammatic top view of an adjustable focusing composite of the invention
- FIG. 4A shows an illustrative diagrammatic side view of an adjustable focusing composite similar to that shown in FIG. 3 taken along line 4 A- 4 A thereof providing a first focal point in accordance with an embodiment of the invention
- FIG. 4B shows an illustrative diagrammatic side view of an adjustable focusing composite of FIG. 4A providing a second focal point in accordance with an embodiment of the invention
- FIGS. 5 A- 5 C show illustrative diagrammatic views of a portion of the adjustable focusing composite of FIGS. 4A and 4B during formation;
- FIGS. 6 and 7 show illustrative diagrammatic top and side views of an adjustable focusing composite in accordance with another embodiment of the invention.
- FIGS. 8 and 9 show illustrative diagrammatic top and side views of an adjustable focusing composite in accordance with a further embodiment of the invention.
- FIG. 10 shows an illustrative diagrammatic side view of an adjustable focusing composite in accordance with a further embodiment of the invention.
- FIG. 11 shows an illustrative diagrammatic view of optical profilometer system in accordance with a further embodiment of the invention.
- Optical profilometer systems in accordance with various embodiments of the invention may employ an adjustable cylindrical focusing composite as shown in FIGS. 1 and 2.
- An advantage of a cylindrical lens is that it allows a line of information to be collected as shown rather than just a single point.
- systems of the invention may employ adjustable focusing composites that provide a focal area that is centralized at a point, a focal area that includes a line as shown in FIGS. 1 and 2, or a focal area that includes any desired one, two or three dimensional shape.
- the use of a focal line eliminates the need to scan in the direction of the focal line in certain circumstances. Also, the inherent tenability of the lens permits the lens to do its own depth scanning rather than relying on expensive external precision machinery.
- an embodiment of an optical profilometery system 10 in accordance with an embodiment of the invention includes an adjustable focusing composite 12 that is positioned between a beam splitter 14 and a subject to be scanned 16 .
- the subject 16 includes a first surface portion 16 A and a second surface portion 16 B.
- a plane wave of a single wavelength of light passes through the beam splitter 14 and the adjustable focusing composite 12 .
- the composite 12 focuses the light at a focal area 18 (e.g., a focal line). If the surface ( 16 A) has any features that are at the same depth of the focal line, then the light striking those features will be reflected back through the composite 12 to become a plane wave that is directed from the beam splitter toward the detection optics. Light that is reflected by surface features ( 16 B) that are not at the depth of the focal line will not become a plane wave upon passing back through the composite 12 .
- the light returning from the composite 12 is directed to a cylindrical lens 20 (of fixed focal length) by the beam splitter 14 .
- Light that is a plane wave (from a surface reflection 16 A at the focal depth of the composite 12 ) will be focused to a focal line at a sensor array 22 .
- a system in accordance with another embodiment of the invention may include a slit unit 24 providing a slit opening, which is positioned at the focal line of the lens 20 , another lens 26 and a sensor array 28 .
- Light that is not a plane wave will not be focused onto the sensor array 22 of FIG. 1 or the sensor array 28 of FIG. 2.
- the optical profilometer By looking at the intensity of the light impinging on the sensor array, one may determine whether there are any points of the surface that intersect the current focal line of the adjustable focusing composite, thereby locating the depth of those points.
- the optical profilometer then sweeps the focal length of the composite through a range of values to obtain information on the depth of the sample surface at all points on the plane defined by the focal line and the depth direction.
- the sample may then be moved to a new location and the depth scan may be again performed.
- the depth scan may be again performed.
- a complete surface map of the entire sample may be created by stitching together the depth data from each step. This technique may be employed, for example, at each etch step in a micro-fabrication process.
- an adjustable focusing composite in accordance with an embodiment of the invention may be a tunable cylindrical zone plate 30 that includes diffractive elements 32 , flexure springs 34 , and a pair of comb drive mechanisms 36 .
- the center element of the diffractive elements 32 may be fixed to an anchor structure 38 , while each of the remaining diffractive elements is coupled to its adjacent diffractive elements via the flexure springs 34 .
- the comb drive mechanisms 36 each include a comb element 40 that moves responsive to and with respect to a drive element 42 . This movement of the comb element 40 with respect to the drive element 42 (and the anchor structure 38 ) causes an attachment bar 44 to pull on the outermost diffractive elements.
- An optical aperture for the adjustable focusing composite may include a large portion of the area defined by the diffractive elements, and may for example be between about 100 ⁇ m and 500 ⁇ m.
- the focal line may be adjusted from a first position having a focal distance f d1 (as shown at 50 in FIG. 4A) to a second position having a focal distance f d2 (as shown at 52 in FIG. 4B) by actuating the comb drive mechanisms 36 to draw the diffractive elements 32 away from one another as shown at A in FIG. 4B.
- the time to record the surface profile of a sample may depend on the scanning time. Optical profilometer systems that record a line of data for each sample step should be faster than profilometer systems that retrieve information at only a point at a time. Also, because the tunable cylindrical zone plates are microfabricated, they lend themselves to being grouped together in a dense array. An array of the tunable cylindrical zone plates within the proposed optical profilometer would significantly reduce the scan times required to record the profile of a sample.
- the resolution of the optical profilometer in both the depth direction and the lateral direction depends on the numerical aperture of the tunable cylindrical zone plate as well as the wavelength of the light used to interrogate the surface. It is anticipated that sub-micron resolution should be achievable.
- the range between the highest to lowest points in depth may be on the order of hundreds of micrometers, while the lateral ranges may be arbitrarily large depending on the range of the stepping machinery of the optical profilometer.
- a closed loop feedback control system may be used with an optical profilometer in accordance with an embodiment. This feedback will be used to obtain, with high accuracy, the precise depth of maximum sensor intensity of points on a surface. Also, information from the sensor array may be used to tune the focal length for a step at the expected value of scanning range in the depth direction, and also will improve resolution by fine tuning the scanning at the surface depth. Similar feedback control systems may be implemented in AFM and fixed-current STM systems.
- the adjustable focusing composite may include a piezoelectric drive mechanism.
- the diffractive elements may be reflective, opaque or transparent in various embodiments, providing focusing via various combinations of amplitude or phase modulation.
- Optical profilometer systems of the invention provide increased scanning speed and lower manufacturing costs due, at least in part, to the elimination of expensive precision components that are used in conventional profilometry systems.
- a structure of the invention may be formed by depositing a grating material in a pattern on a sacrificial substrate. A further sacrificial layer is then deposited onto the pattern. The sacrificial layers are then removed leaving an array of diffractive elements.
- a sacrificial layer 62 comprising for example a 0.2 micron silicon dioxide (SiO 2 ) layer, is deposited or grown onto a base structure 60 , which may be a diffusion barrier for a piezoelectric material, Pb(Zr, Ti)O 3 .
- a grating material 32 such as a platinum bottom electrode, is then formed on the layer 62 , for example by patterned evaporation through a mask using an HF/HCL reagent, and a second sacrificial layer 64 is then deposited on the grating material 32 , filling the cavities between the grating elements 32 as shown in FIG. 5B.
- the structure may then be exposed to a chemical wash, using for example potassium hydroxide, that dissolves and removes the sacrificial layers 62 and 64 leaving an array formed of a plurality of diffractive elements 32 as shown in FIG. 5C.
- a chemical wash using for example potassium hydroxide, that dissolves and removes the sacrificial layers 62 and 64 leaving an array formed of a plurality of diffractive elements 32 as shown in FIG. 5C.
- the ends of each of the grating elements are joined to one another in various ways in different embodiments as discussed below.
- the diffractive elements 66 are coupled together at each end, providing rectangular openings between which are defined the diffractive elements 66 .
- a 0.2 micron oxide is first grown as a diffusion barrier for the piezoelectric material.
- Platinum bottom electrodes 70 are then deposited via evaporation and patterned.
- Piezoelectric material 72 Pb(Zr, Ti)O 3 is then deposited and patterned with a HF/HCL reagent.
- the top electrodes 74 and the gratings 66 are then deposited and patterned similarly like the bottom electrode.
- the final step involves of a potassium hydroxide etch from the backside of the wafer to release the membrane structure.
- the electrodes 70 are anchored.
- the electrodes 74 are caused to move relative to the electrodes 70 as shown at B in FIG. 6 due to the presence of the piezoelectric material 72 .
- the relative spacing between the diffractive elements 66 may be adjusted to provide different focal areas.
- the stretching is achieved through flexure of the sides of the layer 66 .
- the ends of the diffractive elements are coupled to one another via flexure springs, which are also formed during the deposition processes discussed above with reference to FIGS. 5 A- 5 C.
- the diffractive elements at either end of the structure are each further coupled to a comb drive mechanism that includes, for example, drive extensions 46 , and conductive fingers 48 that are received within between the extensions 46 as shown in FIG. 3.
- the drive extensions 46 are coupled to drive units 42
- the conductive fingers 48 are coupled to the outside edge of the diffractive elements as shown in FIG. 3.
- the drive mechanism and optional anchors are also formed by the above discussed deposition processes.
- a structure of the invention may be formed using a silicon-on-insulator wafer that has a 10 micron thick device layer and a 0.5 micro thick buried oxide.
- the device layer may be first etched using deep reactive ion etching technology, which allows the development of diffractive elements and flexure springs that are 10 microns thick. This increases the vertical stiffness of the structure and inhibits potential stiction problems during the release step.
- lateral bumps may be employed to further reduce lateral stiction.
- the resulting structure is essentially residual-stress free because there is no film deposition.
- the design further avoids etching non-uniformities due to different exposure areas.
- the deep reactive etching technology process is followed by a hydrofluoric acid etching step to release the moving parts. Since the lateral dimension of the movable parts is much smaller than that of the fixed parts, large process latitude exists during the time-controlled release process.
- an aluminum film is deposited to form electrodes and may also be used to form the surface on the gratings in certain embodiments.
- the flexure stiffness of the flexure springs, the comb-drive pairs, and the grating period are each important design parameters.
- the flexure stiffness is selected based on a trade-off: low tuning voltage ( ⁇ 100 V) requires the device to be compliant. Additionally, the device should be stiff enough that the resonant frequency remains high (10 kHz or higher).
- the driving force is rendered by the two comb-drives on the sides. Comb-drives draw very little current and therefore minimize power consumption, though the force delivered is relatively small (micro-Newtons or less).
- the minimum grating period is set by the resolution of the available lithography tool. Since the flexures on the sides of the grating must be defined, the minimum grating pitch may be 4 times the design rule for 75% duty cycle or 6 times for the design rule for 50% duty cycle.
- the driving force is via the deposited thin-film piezoelectric actuators.
- the diffractive grating may be etched above the membrane such that its period could be tuned progressively to a desired value in response to stretching of the membrane.
- Such devices may be designed such that the deformation may be on the order of 1-2 nm per period at an applied voltage of 0.05 volts. Further designs of the device may include free cantilever devices or perforated membrane devices.
- the diffractive elements may be reflective or opaque to provide amplitude modulation of the received illumination. In other embodiments, the diffractive elements may be clear to provide phase modulation of the received illumination. In various embodiments, the composite itself may be transmissive or reflective.
- the diffractive elements may also be a variety of shapes other than those discussed above, and may include, for example, concentric circular Fresnel zone plates that are stretched radially to change the spacing of circular diffractive elements, or photon sieves, which include randomly placed holes (or spots) that decrease in radius the further the holes (or spots) are from a central point. Similarly, these photon sieves may be formed of a stretchable material that may be stretched to change the spacing between the diffractive elements (holes or spots).
- the spacing between the diffractive elements may be changed by moving or stretching the material in outward and inward radial directions to provide a range of centralized focal areas.
- Photon sieves may also be used to provide a variety of other shapes of focal areas, including focal lines.
- a focusing composite 80 in accordance with a further embodiment of the invention includes a plurality of diffractive elements 82 that are defined by variations in thickness in a base substrate 84 .
- the diffractive elements 82 and substrate 84 may both be transparent.
- focusing composite 86 in accordance with a further embodiment of the invention may include a plurality of diffractive elements 88 that are defined by variations in material with respect to a substrate 90 .
- a profilometer system 100 in accordance with a further embodiment of the invention may involve the incident electromagnetic field contacting an adjustable focusing composite 112 in a direction other than normal to the surface of the composite 112 , and then reflecting via a mirror 114 toward a cylindrical lens 120 , slit unit 124 , and another cylindrical lens 126 that directs the field to sensor array 128 .
- the operation of the system 100 is similar to that discussed above with reference to FIG. 2 with the focusing composite 112 being adjustable in a direction as generally indicated at C.
- the field that is reflected from the surface is not directed along the same path from which it approached the surface, permitting the system to not require a beam splitter.
Abstract
Description
- This application claims priority to U.S. Provisional Application Ser. No. 60/375,792 filed Apr. 26, 2002.
- The invention relates to profilometers, and relates in particular to optical profilometers. Profilometers may be used for a variety of applications involving the determination of the depth or contours of a surface. Obtaining information regarding a profile of a surface is important in many areas of manufacturing and research. For example, U.S. Pat. No. 5,565,987 discloses a profilometer system that includes a stylus for closely tracking a surface on a sub-nanometer scale, and U.S. Pat. No. 5,705,741 discloses a profilometer system that includes a constant force mechanism for biasing a stylus arm.
- Optical profilometers provide sensitive non-contact profilometry. Certain conventional optical profilometer systems, however, such as those disclosed inConfocal Microscopy with a Refractive Microles-Pinhole Array, by M. Eisner, N. Lindlein, and J. Schwider, Optics Letters, v.23, no. 10 (May 1998); and Lithographic Patterning and Confocal Imaging with Zone Plates, D. Gil, R. Menon, D. Carter, and H. Smith, J. Vacuum Science and Technology B, 18(6) p. 2881-2885 (November/December. 2000) require that a lens array be physically moved to change the focal area during scanning. Such mechanical movement may be time consuming and difficult to achieve in an assembly that is efficient and economical to produce. A variety of optical profilometers have been developed that may avoid moving a lens. For example, U.S. Pat. No. 4,579,454 discloses an optical profilometer in which the position of a focal point within a detector area is determined. U.S. Pat. No. 6,229,617 discloses an optical profilometer system in which light reflected from a surface is interfered with reference laser energy to produce an interference pattern.
- There remains a need however, for an optical profilometer that more efficiently and economically determines the spatial profile an area within its field of view.
- The invention provides an adjustable focusing composite for use in an optical profilometer system. The adjustable focusing composite includes a plurality of elements that are mutually spaced from another in a first position and provides a first focal area for an incident electromagnetic field having a first frequency incident at a first angle with respect to the plurality of elements. The adjustable focusing composite also includes an actuation unit for changing the focal area of the plurality of elements to provide a second,focal area for the incident electromagnetic field having the first frequency incident at the first angle with respect to the plurality of elements.
- The following description may be further understood with reference to the accompanying drawings in which:
- FIGS. 1 and 2 show illustrative diagrammatic views of optical profilometer systems in accordance with various embodiments of the invention;
- FIG. 3 shows an illustrative diagrammatic top view of an adjustable focusing composite of the invention;
- FIG. 4A shows an illustrative diagrammatic side view of an adjustable focusing composite similar to that shown in FIG. 3 taken along line4A-4A thereof providing a first focal point in accordance with an embodiment of the invention;
- FIG. 4B shows an illustrative diagrammatic side view of an adjustable focusing composite of FIG. 4A providing a second focal point in accordance with an embodiment of the invention;
- FIGS.5A-5C show illustrative diagrammatic views of a portion of the adjustable focusing composite of FIGS. 4A and 4B during formation;
- FIGS. 6 and 7 show illustrative diagrammatic top and side views of an adjustable focusing composite in accordance with another embodiment of the invention;
- FIGS. 8 and 9 show illustrative diagrammatic top and side views of an adjustable focusing composite in accordance with a further embodiment of the invention;
- FIG. 10 shows an illustrative diagrammatic side view of an adjustable focusing composite in accordance with a further embodiment of the invention; and
- FIG. 11 shows an illustrative diagrammatic view of optical profilometer system in accordance with a further embodiment of the invention.
- The drawings are shown for illustrative purposes and are not to scale.
- Optical profilometer systems in accordance with various embodiments of the invention may employ an adjustable cylindrical focusing composite as shown in FIGS. 1 and 2. An advantage of a cylindrical lens is that it allows a line of information to be collected as shown rather than just a single point. In further embodiments, systems of the invention may employ adjustable focusing composites that provide a focal area that is centralized at a point, a focal area that includes a line as shown in FIGS. 1 and 2, or a focal area that includes any desired one, two or three dimensional shape. The use of a focal line eliminates the need to scan in the direction of the focal line in certain circumstances. Also, the inherent tenability of the lens permits the lens to do its own depth scanning rather than relying on expensive external precision machinery.
- As shown in FIG. 1 an embodiment of an
optical profilometery system 10 in accordance with an embodiment of the invention includes an adjustable focusingcomposite 12 that is positioned between abeam splitter 14 and a subject to be scanned 16. Thesubject 16 includes afirst surface portion 16A and asecond surface portion 16B. - During use, a plane wave of a single wavelength of light passes through the
beam splitter 14 and the adjustable focusingcomposite 12. Thecomposite 12 focuses the light at a focal area 18 (e.g., a focal line). If the surface (16A) has any features that are at the same depth of the focal line, then the light striking those features will be reflected back through thecomposite 12 to become a plane wave that is directed from the beam splitter toward the detection optics. Light that is reflected by surface features (16B) that are not at the depth of the focal line will not become a plane wave upon passing back through thecomposite 12. - The light returning from the
composite 12 is directed to a cylindrical lens 20 (of fixed focal length) by thebeam splitter 14. Light that is a plane wave (from asurface reflection 16A at the focal depth of the composite 12) will be focused to a focal line at asensor array 22. As shown in FIG. 2, a system in accordance with another embodiment of the invention may include aslit unit 24 providing a slit opening, which is positioned at the focal line of thelens 20, anotherlens 26 and asensor array 28. Light that is not a plane wave will not be focused onto thesensor array 22 of FIG. 1 or thesensor array 28 of FIG. 2. - By looking at the intensity of the light impinging on the sensor array, one may determine whether there are any points of the surface that intersect the current focal line of the adjustable focusing composite, thereby locating the depth of those points. The optical profilometer then sweeps the focal length of the composite through a range of values to obtain information on the depth of the sample surface at all points on the plane defined by the focal line and the depth direction.
- Once the depth data for a particular orientation of a sample surface and focusing composite is completely collected, the sample may then be moved to a new location and the depth scan may be again performed. By carefully stepping the sample beneath the adjustable focusing composite, a complete surface map of the entire sample may be created by stitching together the depth data from each step. This technique may be employed, for example, at each etch step in a micro-fabrication process.
- As shown in FIG. 3, an adjustable focusing composite in accordance with an embodiment of the invention may be a tunable
cylindrical zone plate 30 that includesdiffractive elements 32,flexure springs 34, and a pair ofcomb drive mechanisms 36. The center element of thediffractive elements 32 may be fixed to ananchor structure 38, while each of the remaining diffractive elements is coupled to its adjacent diffractive elements via theflexure springs 34. Thecomb drive mechanisms 36 each include acomb element 40 that moves responsive to and with respect to adrive element 42. This movement of thecomb element 40 with respect to the drive element 42 (and the anchor structure 38) causes an attachment bar 44 to pull on the outermost diffractive elements. Because the diffractive elements are coupled to one another via flexure springs, each diffractive element is then pulled away from its adjacent diffractive element by a small amount. When thedrive elements 42 release thecomb elements 40, thediffractive elements 32 are drawn toward each other via the flexure springs 34. An optical aperture for the adjustable focusing composite may include a large portion of the area defined by the diffractive elements, and may for example be between about 100 μm and 500 μm. - As shown in FIGS. 4A and 4B, the focal line may be adjusted from a first position having a focal distance fd1 (as shown at 50 in FIG. 4A) to a second position having a focal distance fd2 (as shown at 52 in FIG. 4B) by actuating the
comb drive mechanisms 36 to draw thediffractive elements 32 away from one another as shown at A in FIG. 4B. - The time to record the surface profile of a sample may depend on the scanning time. Optical profilometer systems that record a line of data for each sample step should be faster than profilometer systems that retrieve information at only a point at a time. Also, because the tunable cylindrical zone plates are microfabricated, they lend themselves to being grouped together in a dense array. An array of the tunable cylindrical zone plates within the proposed optical profilometer would significantly reduce the scan times required to record the profile of a sample.
- The resolution of the optical profilometer in both the depth direction and the lateral direction depends on the numerical aperture of the tunable cylindrical zone plate as well as the wavelength of the light used to interrogate the surface. It is anticipated that sub-micron resolution should be achievable. The range between the highest to lowest points in depth may be on the order of hundreds of micrometers, while the lateral ranges may be arbitrarily large depending on the range of the stepping machinery of the optical profilometer.
- To further reduce scanning time and improve resolution, a closed loop feedback control system may be used with an optical profilometer in accordance with an embodiment. This feedback will be used to obtain, with high accuracy, the precise depth of maximum sensor intensity of points on a surface. Also, information from the sensor array may be used to tune the focal length for a step at the expected value of scanning range in the depth direction, and also will improve resolution by fine tuning the scanning at the surface depth. Similar feedback control systems may be implemented in AFM and fixed-current STM systems.
- In further embodiments, the adjustable focusing composite may include a piezoelectric drive mechanism. The diffractive elements may be reflective, opaque or transparent in various embodiments, providing focusing via various combinations of amplitude or phase modulation. Optical profilometer systems of the invention provide increased scanning speed and lower manufacturing costs due, at least in part, to the elimination of expensive precision components that are used in conventional profilometry systems.
- A structure of the invention may be formed by depositing a grating material in a pattern on a sacrificial substrate. A further sacrificial layer is then deposited onto the pattern. The sacrificial layers are then removed leaving an array of diffractive elements. In particular, as shown in FIG. 5A a
sacrificial layer 62, comprising for example a 0.2 micron silicon dioxide (SiO2) layer, is deposited or grown onto abase structure 60, which may be a diffusion barrier for a piezoelectric material, Pb(Zr, Ti)O3. Agrating material 32, such as a platinum bottom electrode, is then formed on thelayer 62, for example by patterned evaporation through a mask using an HF/HCL reagent, and a secondsacrificial layer 64 is then deposited on thegrating material 32, filling the cavities between thegrating elements 32 as shown in FIG. 5B. - The structure may then be exposed to a chemical wash, using for example potassium hydroxide, that dissolves and removes the
sacrificial layers diffractive elements 32 as shown in FIG. 5C. The ends of each of the grating elements are joined to one another in various ways in different embodiments as discussed below. - With reference to FIGS. 6 and 7, in the piezoelectric version, the
diffractive elements 66 are coupled together at each end, providing rectangular openings between which are defined thediffractive elements 66. During fabrication, a 0.2 micron oxide is first grown as a diffusion barrier for the piezoelectric material.Platinum bottom electrodes 70 are then deposited via evaporation and patterned.Piezoelectric material 72 Pb(Zr, Ti)O3, is then deposited and patterned with a HF/HCL reagent. Thetop electrodes 74 and thegratings 66 are then deposited and patterned similarly like the bottom electrode. The final step involves of a potassium hydroxide etch from the backside of the wafer to release the membrane structure. - During use, the
electrodes 70 are anchored. When a voltage is applied across theelectrodes electrodes 74 are caused to move relative to theelectrodes 70 as shown at B in FIG. 6 due to the presence of thepiezoelectric material 72. In this way, the relative spacing between thediffractive elements 66 may be adjusted to provide different focal areas. The stretching is achieved through flexure of the sides of thelayer 66. - In the electrostatic version, the ends of the diffractive elements are coupled to one another via flexure springs, which are also formed during the deposition processes discussed above with reference to FIGS.5A-5C. The diffractive elements at either end of the structure are each further coupled to a comb drive mechanism that includes, for example, drive
extensions 46, andconductive fingers 48 that are received within between theextensions 46 as shown in FIG. 3. Thedrive extensions 46 are coupled to driveunits 42, and theconductive fingers 48 are coupled to the outside edge of the diffractive elements as shown in FIG. 3. The drive mechanism and optional anchors are also formed by the above discussed deposition processes. - In further embodiments, a structure of the invention may be formed using a silicon-on-insulator wafer that has a 10 micron thick device layer and a 0.5 micro thick buried oxide. The device layer may be first etched using deep reactive ion etching technology, which allows the development of diffractive elements and flexure springs that are 10 microns thick. This increases the vertical stiffness of the structure and inhibits potential stiction problems during the release step. In further embodiments, lateral bumps may be employed to further reduce lateral stiction. The resulting structure is essentially residual-stress free because there is no film deposition. Moreover, because the buried oxide behaves essentially like a good etch stop, the design further avoids etching non-uniformities due to different exposure areas. The deep reactive etching technology process is followed by a hydrofluoric acid etching step to release the moving parts. Since the lateral dimension of the movable parts is much smaller than that of the fixed parts, large process latitude exists during the time-controlled release process. After releasing, an aluminum film is deposited to form electrodes and may also be used to form the surface on the gratings in certain embodiments.
- The flexure stiffness of the flexure springs, the comb-drive pairs, and the grating period are each important design parameters. The stiffness of the flexure may be estimated by k=Ew3t/L3, where the effective spring constant for a grating period is on the left side, E is the Young's modulus of the material, t is the thickness of the structure, w is the width of the flexure beam, and L is the length of the folded beam. The flexure stiffness is selected based on a trade-off: low tuning voltage (<100 V) requires the device to be compliant. Additionally, the device should be stiff enough that the resonant frequency remains high (10 kHz or higher).
- The driving force is rendered by the two comb-drives on the sides. Comb-drives draw very little current and therefore minimize power consumption, though the force delivered is relatively small (micro-Newtons or less). The force may be estimated as F=NεtV2/2 g where N is the number of fingers, ε is the permittivity, t is the thickness, V is the applied voltage, and g is the gap. The minimum grating period is set by the resolution of the available lithography tool. Since the flexures on the sides of the grating must be defined, the minimum grating pitch may be 4 times the design rule for 75% duty cycle or 6 times for the design rule for 50% duty cycle. In the piezoelectric version, the driving force is via the deposited thin-film piezoelectric actuators. The diffractive grating may be etched above the membrane such that its period could be tuned progressively to a desired value in response to stretching of the membrane. Such devices may be designed such that the deformation may be on the order of 1-2 nm per period at an applied voltage of 0.05 volts. Further designs of the device may include free cantilever devices or perforated membrane devices.
- The diffractive elements may be reflective or opaque to provide amplitude modulation of the received illumination. In other embodiments, the diffractive elements may be clear to provide phase modulation of the received illumination. In various embodiments, the composite itself may be transmissive or reflective. The diffractive elements may also be a variety of shapes other than those discussed above, and may include, for example, concentric circular Fresnel zone plates that are stretched radially to change the spacing of circular diffractive elements, or photon sieves, which include randomly placed holes (or spots) that decrease in radius the further the holes (or spots) are from a central point. Similarly, these photon sieves may be formed of a stretchable material that may be stretched to change the spacing between the diffractive elements (holes or spots). In these cases, the spacing between the diffractive elements may be changed by moving or stretching the material in outward and inward radial directions to provide a range of centralized focal areas. Photon sieves may also be used to provide a variety of other shapes of focal areas, including focal lines.
- As shown in FIGS. 8 and 9, a focusing
composite 80 in accordance with a further embodiment of the invention includes a plurality ofdiffractive elements 82 that are defined by variations in thickness in abase substrate 84. Thediffractive elements 82 andsubstrate 84 may both be transparent. As shown in FIG. 10, focusing composite 86 in accordance with a further embodiment of the invention may include a plurality ofdiffractive elements 88 that are defined by variations in material with respect to asubstrate 90. - As shown in FIG. 11, a
profilometer system 100 in accordance with a further embodiment of the invention may involve the incident electromagnetic field contacting an adjustable focusing composite 112 in a direction other than normal to the surface of the composite 112, and then reflecting via amirror 114 toward acylindrical lens 120, slitunit 124, and anothercylindrical lens 126 that directs the field tosensor array 128. The operation of thesystem 100 is similar to that discussed above with reference to FIG. 2 with the focusing composite 112 being adjustable in a direction as generally indicated at C. In thesystem 100, however, the field that is reflected from the surface is not directed along the same path from which it approached the surface, permitting the system to not require a beam splitter. - Those skilled in the art will appreciate that numerous modifications and variations may be made to the above disclosed embodiments without departing from the spirit and scope of the invention.
Claims (16)
Priority Applications (1)
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US10/423,670 US6943968B2 (en) | 2002-04-26 | 2003-04-25 | Adjustable focusing composite for use in an optical profilometer system and method |
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US37579202P | 2002-04-26 | 2002-04-26 | |
US10/423,670 US6943968B2 (en) | 2002-04-26 | 2003-04-25 | Adjustable focusing composite for use in an optical profilometer system and method |
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US20040021053A1 true US20040021053A1 (en) | 2004-02-05 |
US6943968B2 US6943968B2 (en) | 2005-09-13 |
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US (1) | US6943968B2 (en) |
AU (1) | AU2003234256A1 (en) |
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Cited By (2)
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US20090262367A1 (en) * | 2006-05-30 | 2009-10-22 | Abramo Barbaresi | Device for Acquiring a Three-Dimensional Video Constituted by 3-D Frames Which Contain the Shape and Color of the Acquired Body |
US20170363845A1 (en) * | 2015-01-20 | 2017-12-21 | Impresa Ingegneria Italia S.R.L. | Image-acquiring equipment equipped with telecentric optical objective with primary cylindrical lens |
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US7483147B2 (en) * | 2004-11-10 | 2009-01-27 | Korea Advanced Institute Of Science And Technology (Kaist) | Apparatus and method for measuring thickness and profile of transparent thin film using white-light interferometer |
EP2263107A4 (en) * | 2008-04-10 | 2016-12-28 | Services Petroliers Schlumberger | Method for characterizing a geological formation traversed by a borehole |
US8725477B2 (en) | 2008-04-10 | 2014-05-13 | Schlumberger Technology Corporation | Method to generate numerical pseudocores using borehole images, digital rock samples, and multi-point statistics |
US8311788B2 (en) | 2009-07-01 | 2012-11-13 | Schlumberger Technology Corporation | Method to quantify discrete pore shapes, volumes, and surface areas using confocal profilometry |
US8649024B2 (en) * | 2010-12-03 | 2014-02-11 | Zygo Corporation | Non-contact surface characterization using modulated illumination |
DE102012013530B3 (en) * | 2012-07-05 | 2013-08-29 | Helmholtz-Zentrum Berlin Für Materialien Und Energie Gmbh | Apparatus for measuring resonant inelastic X-ray scattering of a sample |
Citations (28)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4110617A (en) * | 1976-03-17 | 1978-08-29 | S.A. Des Anciens Establissements Paul Wurth | Infra-red profilometer |
US4268968A (en) * | 1979-08-20 | 1981-05-26 | Pullman Incorporated | Railway wheel profilometer and diameter gage |
US4290067A (en) * | 1978-12-12 | 1981-09-15 | Paul Wurth, S.A. | Radiant energy profilometer |
US4288926A (en) * | 1979-11-02 | 1981-09-15 | The United States Of America As Represented By The Secretary Of Transportation | Longitudinal rail profilometer |
US4332374A (en) * | 1979-04-13 | 1982-06-01 | Paul Wurth S.A. | Profilometer mounting technique and apparatus |
US4571695A (en) * | 1982-07-09 | 1986-02-18 | Purdue Research Foundation | Non-contact road profilometer and deflection meter |
US4576479A (en) * | 1982-05-17 | 1986-03-18 | Downs Michael J | Apparatus and method for investigation of a surface |
US4579545A (en) * | 1983-09-01 | 1986-04-01 | Allied Corporation | Flexible coupling using toroidal joint |
US4851773A (en) * | 1981-09-28 | 1989-07-25 | Samuel Rothstein | Rotating head profilometer probe |
US4916319A (en) * | 1988-04-22 | 1990-04-10 | Tauton Technologies, Inc. | Beam intensity profilometer |
US5020904A (en) * | 1989-09-06 | 1991-06-04 | Mcmahan Jr Robert K | Dynamic laser speckle profilometer and method |
US5054926A (en) * | 1987-03-24 | 1991-10-08 | Commonwealth Scientific And Industrial Research Organisation | Distance measuring device |
US5105552A (en) * | 1987-09-09 | 1992-04-21 | Institut Superieur D'etat De Surface (I S E S) | Procedure and sliding support for a profilometer |
US5166751A (en) * | 1989-12-23 | 1992-11-24 | Carl-Zeiss-Stiftung | Interferometric profilometer sensor |
US5264678A (en) * | 1991-09-26 | 1993-11-23 | Applied Research, Inc. | Weld-bead profilometer |
US5309755A (en) * | 1992-10-02 | 1994-05-10 | Tencor Instruments | Profilometer stylus assembly insensitive to vibration |
US5349440A (en) * | 1991-02-08 | 1994-09-20 | Hughes Aircraft Company | Interferometric laser profilometer including a multimode laser diode emitting a range of stable wavelengths |
US5469250A (en) * | 1993-05-17 | 1995-11-21 | Rockwell International Corporation | Passive optical wind profilometer |
US5539516A (en) * | 1994-04-29 | 1996-07-23 | International Business Machines Corporation | Scanning pulsed profilometer |
US5565987A (en) * | 1995-03-23 | 1996-10-15 | Anvik Corporation | Fabry-Perot probe profilometer having feedback loop to maintain resonance |
US5705741A (en) * | 1994-12-22 | 1998-01-06 | Tencor Instruments | Constant-force profilometer with stylus-stabilizing sensor assembly, dual-view optics, and temperature drift compensation |
US5829149A (en) * | 1993-09-27 | 1998-11-03 | Tyson; Graham Roland | Walking profilometer |
US5861549A (en) * | 1996-12-10 | 1999-01-19 | Xros, Inc. | Integrated Silicon profilometer and AFM head |
US5880846A (en) * | 1997-07-09 | 1999-03-09 | Yeda Research And Development Co. Ltd. | Method and apparatus for color-coded optical profilometer |
US5955661A (en) * | 1997-01-06 | 1999-09-21 | Kla-Tencor Corporation | Optical profilometer combined with stylus probe measurement device |
US6229617B1 (en) * | 1999-02-04 | 2001-05-08 | The Regents Of The University Of California | High resolution non-contact interior profilometer |
US6392749B1 (en) * | 1997-09-22 | 2002-05-21 | Candela Instruments | High speed optical profilometer for measuring surface height variation |
US6469794B1 (en) * | 2001-06-28 | 2002-10-22 | Martin S. Piltch | High resolution non-contact interior profilometer |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
NL8501100A (en) | 1985-04-15 | 1986-11-03 | Optische Ind De Oude Delft Nv | METHOD AND SYSTEM FOR MEASURING THE SURFACE PROFILE OF A SURFACE |
DE4123052A1 (en) | 1990-09-13 | 1992-03-19 | Messerschmitt Boelkow Blohm | Integrated sensor and focus adjuster for high power laser - determines focusing error using quadrant detector and sends corrective control signals to piezoelectric or magnetostrictive actuators |
FR2688598A1 (en) | 1992-03-13 | 1993-09-17 | Thomson Csf | VARIABLE FOCAL FRESNEL PLATE. |
-
2003
- 2003-04-25 US US10/423,670 patent/US6943968B2/en not_active Expired - Lifetime
- 2003-04-25 AU AU2003234256A patent/AU2003234256A1/en not_active Abandoned
- 2003-04-25 WO PCT/US2003/013077 patent/WO2003091661A1/en not_active Application Discontinuation
Patent Citations (29)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4110617A (en) * | 1976-03-17 | 1978-08-29 | S.A. Des Anciens Establissements Paul Wurth | Infra-red profilometer |
US4290067A (en) * | 1978-12-12 | 1981-09-15 | Paul Wurth, S.A. | Radiant energy profilometer |
US4332374A (en) * | 1979-04-13 | 1982-06-01 | Paul Wurth S.A. | Profilometer mounting technique and apparatus |
US4268968A (en) * | 1979-08-20 | 1981-05-26 | Pullman Incorporated | Railway wheel profilometer and diameter gage |
US4288926A (en) * | 1979-11-02 | 1981-09-15 | The United States Of America As Represented By The Secretary Of Transportation | Longitudinal rail profilometer |
US4851773A (en) * | 1981-09-28 | 1989-07-25 | Samuel Rothstein | Rotating head profilometer probe |
US4576479A (en) * | 1982-05-17 | 1986-03-18 | Downs Michael J | Apparatus and method for investigation of a surface |
US4571695A (en) * | 1982-07-09 | 1986-02-18 | Purdue Research Foundation | Non-contact road profilometer and deflection meter |
US4579545A (en) * | 1983-09-01 | 1986-04-01 | Allied Corporation | Flexible coupling using toroidal joint |
US5054926A (en) * | 1987-03-24 | 1991-10-08 | Commonwealth Scientific And Industrial Research Organisation | Distance measuring device |
US5105552A (en) * | 1987-09-09 | 1992-04-21 | Institut Superieur D'etat De Surface (I S E S) | Procedure and sliding support for a profilometer |
US4916319A (en) * | 1988-04-22 | 1990-04-10 | Tauton Technologies, Inc. | Beam intensity profilometer |
US5020904A (en) * | 1989-09-06 | 1991-06-04 | Mcmahan Jr Robert K | Dynamic laser speckle profilometer and method |
US5166751A (en) * | 1989-12-23 | 1992-11-24 | Carl-Zeiss-Stiftung | Interferometric profilometer sensor |
US5349440A (en) * | 1991-02-08 | 1994-09-20 | Hughes Aircraft Company | Interferometric laser profilometer including a multimode laser diode emitting a range of stable wavelengths |
US5264678A (en) * | 1991-09-26 | 1993-11-23 | Applied Research, Inc. | Weld-bead profilometer |
US5309755A (en) * | 1992-10-02 | 1994-05-10 | Tencor Instruments | Profilometer stylus assembly insensitive to vibration |
US5469250A (en) * | 1993-05-17 | 1995-11-21 | Rockwell International Corporation | Passive optical wind profilometer |
US5829149A (en) * | 1993-09-27 | 1998-11-03 | Tyson; Graham Roland | Walking profilometer |
US5539516A (en) * | 1994-04-29 | 1996-07-23 | International Business Machines Corporation | Scanning pulsed profilometer |
US5705741A (en) * | 1994-12-22 | 1998-01-06 | Tencor Instruments | Constant-force profilometer with stylus-stabilizing sensor assembly, dual-view optics, and temperature drift compensation |
US5565987A (en) * | 1995-03-23 | 1996-10-15 | Anvik Corporation | Fabry-Perot probe profilometer having feedback loop to maintain resonance |
US6272907B1 (en) * | 1995-12-11 | 2001-08-14 | Xros, Inc. | Integrated silicon profilometer and AFM head |
US5861549A (en) * | 1996-12-10 | 1999-01-19 | Xros, Inc. | Integrated Silicon profilometer and AFM head |
US5955661A (en) * | 1997-01-06 | 1999-09-21 | Kla-Tencor Corporation | Optical profilometer combined with stylus probe measurement device |
US5880846A (en) * | 1997-07-09 | 1999-03-09 | Yeda Research And Development Co. Ltd. | Method and apparatus for color-coded optical profilometer |
US6392749B1 (en) * | 1997-09-22 | 2002-05-21 | Candela Instruments | High speed optical profilometer for measuring surface height variation |
US6229617B1 (en) * | 1999-02-04 | 2001-05-08 | The Regents Of The University Of California | High resolution non-contact interior profilometer |
US6469794B1 (en) * | 2001-06-28 | 2002-10-22 | Martin S. Piltch | High resolution non-contact interior profilometer |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090262367A1 (en) * | 2006-05-30 | 2009-10-22 | Abramo Barbaresi | Device for Acquiring a Three-Dimensional Video Constituted by 3-D Frames Which Contain the Shape and Color of the Acquired Body |
US7929153B2 (en) * | 2006-05-30 | 2011-04-19 | Abramo Barbaresi | Device for acquiring a three-dimensional video constituted by 3-D frames which contain the shape and color of the acquired body |
US20170363845A1 (en) * | 2015-01-20 | 2017-12-21 | Impresa Ingegneria Italia S.R.L. | Image-acquiring equipment equipped with telecentric optical objective with primary cylindrical lens |
US10495858B2 (en) * | 2015-01-20 | 2019-12-03 | Impresa Ingegneria Italia S.R.L. | Image-acquiring equipment equipped with telecentric optical objective with primary cylindrical lens |
Also Published As
Publication number | Publication date |
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WO2003091661A1 (en) | 2003-11-06 |
AU2003234256A1 (en) | 2003-11-10 |
US6943968B2 (en) | 2005-09-13 |
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